Teens plead guilty to killing teacher over bad grade.

Two Iowa teenagers pleaded guilty to first-degree murder for ambushing and killing their high school Spanish teacher with a baseball bat in a park. The attack was carried out because of a bad grade the teacher had given one of the teenagers. The teacher's body was found hidden in the park. The teenagers were charged as adults and face a recommended sentence of 25-30 years to life with the possibility of parole.